New insights on regional stratigraphy and hydrogeology based on surficial and subsurface sediment mapping in Simcoe County, southern Ontario
Bibliographic record
Abstract
The integration of detailed field mapping of surficial sediments and landforms with information obtained from 14 continuously-cored boreholes are providing key insights into the character and distribution of major sediment packages that form regionally significant hydrostratigraphic units that control groundwater flow systems within Simcoe County. Six major sediment packages are observed, forming successions >160 m thick. A dense sandy till (LCT) overlies the bedrock at most locations in the study area. This till is locally overlain by glaciolacustrine deposits (LGL), which are generally fine-grained although sandy facies are encountered and gravel deposits forming units up to 48 m thick have been observed in two boreholes to date. A fine-grained till (LFT) overlies the lower glaciolacustrine deposits forming a continuous, highly undulating marker bed in the subsurface. The upper surface of the till shows evidence of subaerial weathering at higher elevations (> 170m asl). It is overlain by a fining-upward succession of predominantly sand with lesser gravel and local accumulations of silt and clay-rich diamictons (TF), tentatively assigned to the Thorncliffe Formation. These deposits are overlain by a dense silty sand to sand till (NT) ranging from 2 to 30 m thick and correlative with the Newmarket Till. Particle size analysis of this till shows a progressive coarsening northward. Significant topographic variation in the Newmarket Till is observed across the study area - its upper surface ranging from 150 to 310 m asl. This highly undulating unit imparts a strong control on the character of overlying deposits. Where the till is found at lower elevations, laminated silts and clays form the bulk of the deglacial succession (LA). At higher elevations (>230 m asl), sands and gravels dominate. The lower parts of the succession (LCT, LGL, LFT) do not commonly host significant aquifers. However, the bedrock interface aquifers can meet the demands for rural domestic use, and where the thick gravel deposits are encountered, significant groundwater resources may be present, especially given its occurrence at several tens of meters below modern Georgian Bay. Within the study area, the Thorncliffe Formation deposits form a regionally significant confined aquifer. It occurs regionally beneath both uplands and lowlands and, in many areas, artesian conditions are present. The Newmarket Till forms a regionally significant leaky aquitard, but coarser textures observed in this till in the north appear to significantly decrease its competency as an aquitard. Deglacial sediments generally form thick aquitards in low-lying areas but may form unconfined aquifers at higher elevations. Additionally, erosion of the Newmarket Till during deglaciation has led to preferential groundwater flow path that govern groundwater seepages and create large piping features. Geophysical studies have been carried out to better constrain the architecture of major sediment packages in the subsurface and to characterize the physical properties of the major stratigraphic units. In-situ hydrogeologic tests are planned in order to provide preliminary analysis of aquifer capacities and assess hydraulic connection of aquifers in the region.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".